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Andrey Simakov - One of the best experts on this subject based on the ideXlab platform.
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highly active au ceo2 zro2 yolk shell nanoreactors for the reduction of 4 nitrophenol to 4 Aminophenol
Applied Catalysis B-environmental, 2015Co-Authors: Viridiana Evangelista, Brenda Acosta, Serguei Miridonov, Elena Smolentseva, Sergio Fuentes, Andrey SimakovAbstract:Highly catalytically active yolk–shell Au-CeO2@ZrO2 nanoreactors (gold core encapsulated into porous zirconia shell and doped by ceria) for the 4-nitrophenol reduction to 4-Aminophenol were synthesized. Au cores encapsulated into SiO2 (Au@SiO2) were decorated with ceria via injection of ceria precursor into a void space of silica shell (formed through surface-protected etching of silica by hot water) with its subsequent hydrolysis and thermal treatment (Au-CeO2@SiO2). Au-CeO2@ZrO2 nanoreactors were obtained using Au-CeO2@SiO2 as a template and replacement of SiO2 by ZrO2. The nanoreactors were characterized by STEM-EDS, in situ and ex situ UV–vis spectroscopy, and N2 thermal adsorption. The catalytic activity for decorated Au-CeO2@ZrO2 nanoreactors in the 4-nitrophenol reduction into 4-Aminophenol was found to be ∼3 times higher than for non-decorated Au@ZrO2 nanoreactors. The herein proposed route of nanoreactor core decoration may be applied for the synthesis of nanoreactors with cores modified with different materials in order to make them effective for different catalytic reactions.
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Highly active Au-CeO2@ZrO2 yolk–shell nanoreactors for the reduction of 4-nitrophenol to 4-Aminophenol
Applied Catalysis B-environmental, 2014Co-Authors: Viridiana Evangelista, Brenda Acosta, Serguei Miridonov, Elena Smolentseva, Sergio Fuentes, Andrey SimakovAbstract:Highly catalytically active yolk–shell Au-CeO2@ZrO2 nanoreactors (gold core encapsulated into porous zirconia shell and doped by ceria) for the 4-nitrophenol reduction to 4-Aminophenol were synthesized. Au cores encapsulated into SiO2 (Au@SiO2) were decorated with ceria via injection of ceria precursor into a void space of silica shell (formed through surface-protected etching of silica by hot water) with its subsequent hydrolysis and thermal treatment (Au-CeO2@SiO2). Au-CeO2@ZrO2 nanoreactors were obtained using Au-CeO2@SiO2 as a template and replacement of SiO2 by ZrO2. The nanoreactors were characterized by STEM-EDS, in situ and ex situ UV–vis spectroscopy, and N2 thermal adsorption. The catalytic activity for decorated Au-CeO2@ZrO2 nanoreactors in the 4-nitrophenol reduction into 4-Aminophenol was found to be ∼3 times higher than for non-decorated Au@ZrO2 nanoreactors. The herein proposed route of nanoreactor core decoration may be applied for the synthesis of nanoreactors with cores modified with different materials in order to make them effective for different catalytic reactions.
Safia Ahmed - One of the best experts on this subject based on the ideXlab platform.
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Degradation of 4-Aminophenol by newly isolated Pseudomonas sp. strain ST-4
Enzyme and Microbial Technology, 2005Co-Authors: Sumera Afzal Khan, Muhammad Hamayun, Safia AhmedAbstract:Aromatic compounds and their substituted forms are hazardous to the environment. Biodegradation by microorganisms can be used to remove these pollutants from soil and water. During the present investigations, Pseudomonas sp. strain ST-4 was used for the degradation of 4-Aminophenol. The strain was able to use 4-Aminophenol as growth substrate showing growth up to 400 ppm on mineral salt media plates. In broth, degradation up to 84% was observed. Induction with 4-Aminophenol proved to be effective as it increased the degradation rate more than by the uninduced cell. Biodegradation was found to be more effective than autoxidation of 4-Aminophenol, indicating bioremediation as main process to eliminate aromatic amines. In order to locate the responsible genes for degradation, curing and then isolation of plasmid showed the involvement of plasmid encoded genes in this mechanism since the cured strains do not grow with 4-Aminophenol.
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Isolation and characterization of a Pseudomonas strain that degrades 4-acetamidophenol and 4-Aminophenol
Biodegradation, 2001Co-Authors: Safia Ahmed, M. Afzal Javed, Shazia Tanvir, Abdul HameedAbstract:Though many microorganisms that are capable of using phenol as sole sourceof carbon have been isolated and characterized, only a few organisms degradingsubstituted phenols have been described to date. In this study, one strain ofmicroorganism that is capable of using phenol (3000 ppm), 4-Aminophenol(4000 ppm) and 4-acetamidophenol (4000 ppm) as sole source of carbon andenergy was isolated and characterized. This strain was obtained by enrichmentculture from a site contaminated with compounds like 4-acetamidophenol,4-Aminophenol and phenol in Pakistan at Bhai Pheru. The contaminated siteis able to support large bacterial community as indicated by the viable cellcounts (2 × 10^4–5 × 10^8) per gram of soil. Detailed taxonomic studies identified the organisms as Pseudomonas species designated as strain STI. The isolate also showed growth on other organic compounds like aniline, benzene, benzyl alcohol, benzyl bromide, toluene, ρ-cresol, trichloroethylene and o -xylene. Optimum growth temperature and pH were found to be 30 °C and 7, respectively, while growth at 4, 25 and 35 °C and at pH 8 and 9 was also observed. Non growing suspended cells of strain ST1 degraded 68, 96 and 76.8% of 4-Aminophenol (1000 ppm), phenol (500 ppm) and 4-acetamidophenol (1000 ppm), respectively, in 72 hrs. The isolation and characterization of Pseudomonas speciesstrain ST1, may contribute to efforts on phenolic bioremediation, particularly in anenvironment with very high levels of 4-acetamidophenol and 4-Aminophenol.
Maarit Karppinen - One of the best experts on this subject based on the ideXlab platform.
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Organic–Inorganic Thin Films from TiCl4 and 4‐Aminophenol Precursors: A Model Case of ALD/MLD Hybrid‐Material Growth?
European Journal of Inorganic Chemistry, 2014Co-Authors: Pia Sundberg, Maarit KarppinenAbstract:Invited for the cover of this issue are Pia Sundberg and Maarit Karppinen from the Aalto University, Finland. The cover image shows the deposition cycle of a (Ti–O–C6H4–N=)n-type thin film grown by a combined atomic and molecular layer deposition (ALD/MLD) technique with TiCl4 and 4-Aminophenol as precursors.
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mixing ald mld grown zno and zn 4 Aminophenol layers into various thin film structures
Dalton Transactions, 2013Co-Authors: Pia Sundberg, Anjali Sood, Xuwen Liu, Maarit KarppinenAbstract:Building 2D inorganic–organic hybrids by combining inorganic and organic constituents with molecular-layer precision is an attractive approach to fabricate novel materials with a tailored combination of properties from both entities. Here we demonstrate the potential of the combined atomic and molecular layer deposition (ALD/MLD) technique for the state-of-the-art synthesis of such materials and to fabricate both homogeneous thin-film mixtures and nanolaminates of ZnO and the Zn-4-Aminophenol inorganic–organic hybrid. The thin films are deposited by varying the number of precursor cycles during the depositions. Diethyl zinc and 4-Aminophenol (AP) are used as precursors for the Zn–AP hybrid depositions, and diethyl zinc and water for the ZnO depositions. The characterization of the mixed Zn–AP and ZnO films reveals that crystallinity, density, surface roughness, chemical stability, hardness and contact modulus are sensitively altered by even a minor insertion of Zn–AP hybrid into the ZnO structure. Fabrication of Zn–AP + ZnO nanolaminates with different thicknesses of the Zn–AP and ZnO layers provides us with an even better way to control the hardness and contact modulus, and also to enhance the chemical stability of the films.
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Mixing ALD/MLD-grown ZnO and Zn-4-Aminophenol layers into various thin-film structures.
Dalton Transactions, 2013Co-Authors: Pia Sundberg, Anjali Sood, Xuwen Liu, Maarit KarppinenAbstract:Building 2D inorganic–organic hybrids by combining inorganic and organic constituents with molecular-layer precision is an attractive approach to fabricate novel materials with a tailored combination of properties from both entities. Here we demonstrate the potential of the combined atomic and molecular layer deposition (ALD/MLD) technique for the state-of-the-art synthesis of such materials and to fabricate both homogeneous thin-film mixtures and nanolaminates of ZnO and the Zn-4-Aminophenol inorganic–organic hybrid. The thin films are deposited by varying the number of precursor cycles during the depositions. Diethyl zinc and 4-Aminophenol (AP) are used as precursors for the Zn–AP hybrid depositions, and diethyl zinc and water for the ZnO depositions. The characterization of the mixed Zn–AP and ZnO films reveals that crystallinity, density, surface roughness, chemical stability, hardness and contact modulus are sensitively altered by even a minor insertion of Zn–AP hybrid into the ZnO structure. Fabrication of Zn–AP + ZnO nanolaminates with different thicknesses of the Zn–AP and ZnO layers provides us with an even better way to control the hardness and contact modulus, and also to enhance the chemical stability of the films.
Viridiana Evangelista - One of the best experts on this subject based on the ideXlab platform.
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highly active au ceo2 zro2 yolk shell nanoreactors for the reduction of 4 nitrophenol to 4 Aminophenol
Applied Catalysis B-environmental, 2015Co-Authors: Viridiana Evangelista, Brenda Acosta, Serguei Miridonov, Elena Smolentseva, Sergio Fuentes, Andrey SimakovAbstract:Highly catalytically active yolk–shell Au-CeO2@ZrO2 nanoreactors (gold core encapsulated into porous zirconia shell and doped by ceria) for the 4-nitrophenol reduction to 4-Aminophenol were synthesized. Au cores encapsulated into SiO2 (Au@SiO2) were decorated with ceria via injection of ceria precursor into a void space of silica shell (formed through surface-protected etching of silica by hot water) with its subsequent hydrolysis and thermal treatment (Au-CeO2@SiO2). Au-CeO2@ZrO2 nanoreactors were obtained using Au-CeO2@SiO2 as a template and replacement of SiO2 by ZrO2. The nanoreactors were characterized by STEM-EDS, in situ and ex situ UV–vis spectroscopy, and N2 thermal adsorption. The catalytic activity for decorated Au-CeO2@ZrO2 nanoreactors in the 4-nitrophenol reduction into 4-Aminophenol was found to be ∼3 times higher than for non-decorated Au@ZrO2 nanoreactors. The herein proposed route of nanoreactor core decoration may be applied for the synthesis of nanoreactors with cores modified with different materials in order to make them effective for different catalytic reactions.
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Highly active Au-CeO2@ZrO2 yolk–shell nanoreactors for the reduction of 4-nitrophenol to 4-Aminophenol
Applied Catalysis B-environmental, 2014Co-Authors: Viridiana Evangelista, Brenda Acosta, Serguei Miridonov, Elena Smolentseva, Sergio Fuentes, Andrey SimakovAbstract:Highly catalytically active yolk–shell Au-CeO2@ZrO2 nanoreactors (gold core encapsulated into porous zirconia shell and doped by ceria) for the 4-nitrophenol reduction to 4-Aminophenol were synthesized. Au cores encapsulated into SiO2 (Au@SiO2) were decorated with ceria via injection of ceria precursor into a void space of silica shell (formed through surface-protected etching of silica by hot water) with its subsequent hydrolysis and thermal treatment (Au-CeO2@SiO2). Au-CeO2@ZrO2 nanoreactors were obtained using Au-CeO2@SiO2 as a template and replacement of SiO2 by ZrO2. The nanoreactors were characterized by STEM-EDS, in situ and ex situ UV–vis spectroscopy, and N2 thermal adsorption. The catalytic activity for decorated Au-CeO2@ZrO2 nanoreactors in the 4-nitrophenol reduction into 4-Aminophenol was found to be ∼3 times higher than for non-decorated Au@ZrO2 nanoreactors. The herein proposed route of nanoreactor core decoration may be applied for the synthesis of nanoreactors with cores modified with different materials in order to make them effective for different catalytic reactions.
João M. Madurro - One of the best experts on this subject based on the ideXlab platform.
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Novel electrochemical platform based on copolymer poly(aniline-4-Aminophenol) for application in immunosensor for thyroid hormones
Journal of Solid State Electrochemistry, 2020Co-Authors: Mônica S. Segatto, Ana G. Brito-madurro, Fernanda S. Soler, Carlos A. P. Oliveira, João M. MadurroAbstract:This paper reports the development of a novel electrochemical platform based on graphite electrodes modified with copolymer poly(aniline-4-Aminophenol) and anti-triiodothyronine, integrated into the design of an electrochemical immunosensor for thyroid hormone, allowing free triiodothyronine (T3) detection in real serum samples. The proposed copolymer showed synergistic characteristics among its original polymers, which led to good results in the biofunctionalization step. A specific antibody for T3 was immobilized on copolymer poly(aniline-4-Aminophenol). In the presence of target T3, an immunological reaction occurs with anti-T3, being observed a current decrease proportional to T3 concentration. The decrease was monitored by differential pulse voltammetry, detecting up to 0.60 pg mL^−1 and showing good stability, maintaining 90% of its response after 60 days of storage. This platform shows linear relationship between the anodic current and T3 concentration with linear regression as y = 616.79 − 26.03 x ( r ^2 = 0.9976). The immunosensor shows suitable for detection of thyroid hormones in real serum samples, as well as potential for use in detection of other disease biomarkers.
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A Biosensor Using Poly(4-Aminophenol)/acetylcholinesterase modified graphite electrode for the detection of dichlorvos
Brazilian Archives of Biology and Technology, 2011Co-Authors: Edmar Isaias De Melo, Diego Leoni Franco, André S. Afonso, Helen C. Rezende, Ana G. Brito-madurro, João M. Madurro, Nívia M. M. CoelhoAbstract:The properties of poly(4-Aminophenol) modified graphite electrode as material for the immobilization of acetylcholinesterase were investigated by the Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Atomic Force Microscopy. The polymer was deposited on graphite electrode surface by the oxidation of 4-Aminophenol and then acetylcholinesterase was immobilized on the surface of the electrode. The biosensor coupled in the continuous flow system was employed for the detection of dichlorvos. The detection and quantification limits were 0.8 and 2.4 μmol L-1 dichlorvos, respectively. Graphite electrodes modified with the poly(4-Aminophenol) showed to be an efficient and promising material for immobilization of acetylcholinesterase enzyme. The proposed method requires simple parts which are easy to build, involves only one biosensor and the potentiometric detection is simple.
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A promising bioelectrode based on gene of Mycobacterium leprae immobilized onto poly(4-Aminophenol)
Journal of Applied Polymer Science, 2010Co-Authors: André S. Afonso, João M. Madurro, Luiz Ricardo Goulart, Isabela Maria Bernardes Goulart, Antonio E.h. Machado, Ana G. Brito-madurroAbstract:A new bioelectrode for gene detection of Mycobacterium leprae, also known as Hansen's bacillus, was produced by immobilizing of single-stranded DNA (ssDNA) with 78 bases long (specific gene related to Myco- bacterium leprae) on graphite electrode modified with poly(4-Aminophenol). This biosensing platform was able to recognize complementary DNA molecules via hybridiza- tion process. Hybridization between probe and target was monitored by voltammetry, using ferrocenecarboxyalde- hyde as electrochemical DNA hybridization indicator. The hybridization of nucleic acid probe with the DNA target resulted in significant decrease in the oxidation peak cur- rent of ferrocenecarboxyaldehyde, indicating greater affin- ity of this compound for ssDNA than for double-strand DNA (dsDNA). The linear range of detection for the DNA target was found to be 0.35 - 35 ng/lL. ssDNA hybridiza- tion with the DNA target was also investigated by electro- chemical impedance spectroscopy (EIS), showing significant modification in Nyquist plot, by modification in electrode surface after addition of the complementary target. The effective immobilization of specific gene of Mycobacterium leprae onto graphite electrode modified with poly(4-Aminophenol) and the detection of the hybridiza- tion process with the DNA target, monitored by voltam- metry and EIS indicate that this is a new and promising biosensing platform to gene detection of Hansen's bacillus. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2921-2928, 2010
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Gold electrodes modified with poly(4‐Aminophenol): incorporation of nitrogenated bases and an oligonucleotide
Polymer International, 2007Co-Authors: Lucas Franco Ferreira, Ana G. Brito-madurro, Julien F.c. Boodts, João M. MadurroAbstract:BACKGROUND: Investigations of chemical modification of electrode surfaces and immobilization of nitrogenated bases and oligonucleotides are considered essential for the construction of DNA electrochemical nanodevices. Modification of gold electrode surfaces with poly(4-Aminophenol) was carried out in order to produce polymers capable of immobilizing purine bases and oligonucleotides. RESULTS: Gold electrodes coated with poly(4-Aminophenol) showed improved analytical characteristics and considerably enhanced the electrochemical signals associated with the detection of adenine and guanine by factors of ca 3a ndca 6, respectively, when compared with non-coated gold surfaces. Impedance studies indicated higher charge transfer impedance to modified electrodes containing adenosine monophosphate. Atomic force microscopy images showed that nitrogenated bases have a strong influence over the morphology of the modified electrode surface. It was observed that the modified electrode containing guanine presents globular morphology. CONCLUSION: The modified electrodes increased the amplitude of the current signal of nitrogenated bases when compared to non-coated gold surfaces and produced good response and peaks to the detection of an oligonucleotide. This work presents, for the first time, the electropolymerization of 4-Aminophenol on gold electrodes, as well as the detection of nitrogenated bases and an oligonucleotide incorporated on these modified electrodes. 2007 Society of Chemical Industry Supplementary electronic material for this paper is available in Wiley InterScience at http://www.interscience.wiley.com/jpages/ 0959-8103/suppmat/
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Immobilization of purine bases on a poly-4-Aminophenol matrix
Journal of Materials Science, 2007Co-Authors: Ana G. Brito-madurro, Lucas Franco Ferreira, Sabrina Nunes Vieira, Rafael Gonçalves Ariza, Luiz Ricardo Goulart Filho, João M. MadurroAbstract:Conducting polymers or semi-conductors have various features that make them excellent materials for the immobilization of biomolecules and the rapid transfer of electrons necessary for the production of biosensors. Conducting electroactive polymers of poly-4-Aminophenol have been developed as sensors to detect the purine bases (adenosine triphosphate, ATP and guanosine triphosphate, GTP) of DNA. The electrooxidation of 4-Aminophenol onto a graphite electrode in the presence of perchloric acid yielded thin polymer films. The conductivity was studied by cyclic voltammetry and surface morphology by optical microscopy and interferometry. The immobilization and detection of ATP and GTP on a graphite electrode or modified electrode coated with poly-4-Aminophenol was studied by cyclic voltammetry. Systematic variation of the experimental conditions that influenced the electrode reaction, particularly the pH of the electrolytic solution, showed that the oxidation potentials of the immobilized ATP or GTP in the modified electrodes decreased with increasing pH of the electrolyte. When these conditions were optimized based on voltammetric measurements, modified electrodes coated with poly-4-Aminophenol were found to be efficient in immobilizing purine bases, and increased the amplitude of the ATP and GTP signals by ∼1.5 and ∼24 times, respectively, when compared with non-coated graphite surfaces.
